An iron battery, as an energy storage device and an important component of an electric vehicle, has significant effects on capabilities of the electric vehicle. For example, swelling of battery cells may influence reliability of the battery, such as: (1) causing the cells to move in the battery module, and thus weakening the connection between the cells; (2) causing the size of the cells to be enlarged, and thus increasing requirements for the strength of the module housing and the space occupied of the module housing; (3) causing the clearance between the cells to be difficult to predetermine during designing due to uncontrollable factors: if the clearance is too small, the cells may be difficult to be disposed into the housing or the housing may be damaged; if the clearance is too large, the cells may rock in the module; (4) causing unequal clearances between the cells due to non-uniform swelling of the cells, and thus affecting the thermal uniformity of the battery.
Since the swelling of the general battery is uncontrollable, the reliability of the battery is low. Therefore, the reliability of the electric vehicle is low.